Systems and methods for wideband active probing of devices and circuits in operation

ABSTRACT

Systems and methods for wideband active probing of devices and circuits in operation are provided. One such embodiment includes a probe amplifier housing that at least partially contains a probe amplifier circuitry. The probe amplifier circuitry and the probe housing are configured to be separately arranged and positioned from connected probing and signal monitoring apparatuses. Methods are also provided.

TECHNICAL FIELD

[0001] The present invention is generally related to monitoring andtesting of integrated circuit devices and, more particularly, is relatedto systems and methods for wideband active probing of devices andcircuits in operation.

BACKGROUND OF THE INVENTION

[0002] Continuing advances in integrated circuit (“IC”) technology are amajor cause of the demand for improved systems and methods to monitorand/or test IC devices. For example, chips that are mounted on printedcircuit boards (“PCBs”) are being developed with higher componentdensities and smaller physical dimensions. In turn, the chip packages,i.e. the chip housing and electrical connectors, are being designed inmore complex and compact configurations. A ball grid array (“BGA”), achip package that uses an array of solder balls for the electricalconnectors, is a typical example of such complex and compact chippackage configurations. Other chip package configurations continue touse pins for electrical connectors, but the pins are smaller andarranged to tighter tolerances, and thus, such configurations are alsobecoming more complex and compact.

[0003] IC devices are also being developed that have increasedperformance characteristics. For example, as IC technology advances,central processing unit (“CPU”) chips, for example that are utilized incomputers, are being developed to have increased processing speeds.Furthermore, communication buses that interconnect internal IC deviceswithin a computer system are being developed to support increased speedand bandwidth performance.

[0004] The increased complexity and compactness of chip packageconfigurations and the increased performance characteristics of chipsand other IC devices create challenges to effective and efficientmonitoring and/or testing of such devices. For example, to monitorand/or test an IC device, electrical signals are typically obtained fromthe device and input to monitoring and/or testing equipment, such as anoscilloscope or logic analyzer. A probe is typically connected to suchmonitoring and/or testing equipment and used to obtain the electricalsignals by making physical contact with the electrical connectors orother probe points of the IC device, a process typically referred to as“probing.” Thus, in order to facilitate the effective and efficientmonitoring and/or testing of IC devices, the probe must have physicaland electrical features which overcome the challenges posed by theincreased complexity and compactness of the chip package configurationsand the increased performance characteristics of the IC devices.

[0005] Thus far, various systems and methods have been introduced in anattempt to provide physical and electrical features which overcome thechallenges to effective and efficient monitoring and/or testing of ICdevices, but shortcomings still persist. For example, active probingsystems have been introduced that provide high bandwidth (i.e., highfrequency) signal reception and low loading of probe tips (i.e., lowcurrent through-flow) by positioning the active electronics circuitry asclose as possible to the probe tips. But, this practice results inseveral disadvantages. First, such active probing systems are typicallylarge and bulky, which makes it difficult or impossible to securelyconnect the probe tips to the probe points of a PCB mounted IC device(e.g, by soldering) to perform hands-free probing and, further, to placethe IC device in operation (e.g., by placing the PCB in an enclosure orcard-cage) with the probe tips connected to the probe points to perform“in-situ” (i.e., in actual operation) probing. Second, the cable thatconnects such active probing systems to monitoring and/or testingequipment is usually bulky and inflexible since it contains powerconductors (for power supply to the active electronics circuitry) aswell as one or more coaxial cables (for signal transmission), and theseundesirable features of the connection cable also makes it difficult tomaintain the active probing system in position for probing an IC device.Third, such active probing systems are limited in their probingapplications because the probe tips have a fixed relative physicalpositioning and the electrical characteristics of the probe tips (e.g.,the damping resistance) are fixed relative to the probing system andcannot be varied. Finally, the cost of such active probing systems istypically too high to justify soldering probing attachments to themwithout concern for permanently damaging the probing systems.

[0006] As another example, differential probes (i.e., probes used formeasuring the difference between two signals) have been introduced toprovide high frequency differential probing of IC devices. Suchdifferential probes have a fixed spacing between the probe tips whichlimits the configuration of IC device probe points which can bephysically contacted for probing. In an attempt to overcome thisshortcoming, “bent-wire” probe tip attachments have been introducedwhich can replace or modify the fixed-spacing probe tips. Thesebent-wire probe tip attachments can be attached to existing differentialprobes and bent to vary the spacing between the attached probe tips inorder to contact the intended probe points of an IC device. But, thebent-wire probe tip attachments add undesirable parasitic impedance tothe probe tip circuit which reduces the bandwidth (i.e., the highfrequency signal reception capability) of the differential probe and,thereby, reduces the capability of the differential probe to accuratelyobtain signals from high frequency IC devices. Additionally, thepositioning of the probe tips of the bent-wire probe tip attachments mayundesirably vary during probing of an IC device and thereby result inloss of intended contact with the probe points as well unintendedcontact with other probe points and/or damaging short-circuitconditions.

[0007] As yet another example, wideband (i.e., high bandwidth) probeshave been introduced to measure voltage signals of IC devices. Suchwideband probes typically must contact a probe signal point and a groundprobe point of an IC device with a probe tip and a ground contact,respectively, to obtain voltage signals. A fixed position “spring wire”(e.g., an offset bent wire) or “pogo pin” (i.e., a telescopicallyretracting pin) is typically utilized as a ground contact for thesewideband probes. Since the distance between a signal probe point and aground probe point varies among IC devices, the ground contacts ofexisting wideband probes are typically bent to allow the probe tips tocontact the probe points. There are several disadvantages to utilizing aspring wire as the ground contact in existing wideband probes. First,the length of a practical spring wire is relatively long and, thus, addsundesirable parasitic impedance to the probe circuit, thereby reducingthe bandwidth capability of the probe. Second, the positioning of thespring wire ground contact may undesirably vary (or “skate”) duringprobing of an IC device and thereby result in loss of intended contactwith the ground probe point as well as cause unintended contact withother probe points and/or damaging short-circuit conditions. Third, thespacing set between the probe tip and the ground contact by bending thespring wire may vary, even during routine handling of the probe, thus,making the positioning accuracy unreliable for repeated probing withoutrepeated bending adjustments. Similarly, in utilizing a pogo pin as theground contact in existing wideband probes, the typical practice ofbending the pogo pin to facilitate contact with a ground probe point mayresult in skating, particularly since the bend in the rigid pogo pintypically must be maintained by force applied against the probe pointsduring probing. Because of its rigidity, the pogo pin also does notaccurately maintain the adjusted position during repeated probing.

[0008] Based on the foregoing, it should be appreciated that there is aneed for improved systems and methods which address the aforementioned,as well as other, shortcomings of existing systems and methods.

SUMMARY OF THE INVENTION

[0009] The present invention provides systems and methods for widebandactive probing of devices and circuits in operation.

[0010] Briefly described, one embodiment of the system, among others,includes a probe amplifier housing. Probe amplifier circuitry is atleast partially contained within the probe amplifier housing.Additionally, the probe amplifier circuitry and the probe housing areconfigured to be separately arranged and positioned from connectedprobing and signal monitoring apparatuses.

[0011] Another embodiment of the system includes a probe amplifier unitthat includes probe amplifier circuitry. A first plurality of conductorsare electrically connected to the probe amplifier circuitry and a signalmonitoring apparatus is electrical connected to the probe amplifiercircuitry through the first plurality of conductors. A second pluralityof conductors are electrically connected to the probe amplifiercircuitry and a probing apparatus is electrical connected to the probeamplifier circuitry through the second plurality of conductors.

[0012] Yet another embodiment of the system includes means foramplifying a probe signal. Means for power supply and signaltransmission and means for signal transmission are each electricallyconnected to the means for amplifying a probe signal. Means formonitoring signals are electrically connected to the means foramplifying a probe signal via the means for power supply and signaltransmission. Additionally, means for probing an electrical circuit areelectrically connected to the means for amplifying a probe signal viathe means for signal transmission.

[0013] The present invention can also be viewed as providing methods forwideband active probing of devices and circuits in operation. In thisregard, one embodiment of such a method, among others, can be broadlysummarized by the following steps: providing a probe amplifier unit thatincludes probe amplifier circuitry, electrically connecting a firstplurality of conductors to the probe amplifier circuitry, electricallyconnecting a signal monitoring apparatus to the first plurality ofconductors, electrically connecting a second plurality of conductors tothe probe amplifier circuitry, electrically connecting a probingapparatus to the second plurality of conductors, probing an electricalcircuit with the probing apparatus, and monitoring signals with thesignal monitoring apparatus.

[0014] Other systems, methods, features, and advantages of the presentinvention will be or become apparent to one with skill in the art uponexamination of the following drawings and detailed description. It isintended that all such additional systems, methods, features, andadvantages be included within this description, be within the scope ofthe present invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Many aspects of the invention can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the present invention. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

[0016]FIG. 1A is a perspective view of an embodiment of a probeamplifier unit.

[0017]FIG. 1B is a perspective view of an embodiment of a probeamplifier unit connected to a differential probe unit.

[0018]FIG. 1C is a perspective view of an embodiment of a probeamplifier unit connected to a single-end probe unit.

[0019]FIG. 1D is a perspective view of an embodiment of a probeamplifier unit connected to a differential probe tip unit.

[0020]FIG. 1E is a perspective view of an embodiment of a probeamplifier unit connected to a single-end probe tip unit.

[0021]FIG. 2A is a plan view of an embodiment of the differential probeunit depicted in FIG. 1B.

[0022]FIG. 2B is a cross-sectional view of an embodiment of thedifferential probe unit depicted in FIG. 1B.

[0023]FIG. 2C is an end view of an embodiment of the differential probeunit depicted in FIG. 1B.

[0024]FIG. 2D is a side view of an embodiment of the differential probeunit of FIG. 1B depicted with the probe tips contacting solder points ona printed circuit board.

[0025]FIG. 2E is an end view of an embodiment of the differential probeunit of FIG. 1B with the probe tips positioned at a minimal spacing.

[0026]FIG. 2F is an end view of an embodiment of the differential probeunit of FIG. 1B with the probe tips positioned at a middle spacing.

[0027]FIG. 2G is an end view of an embodiment of the differential probeunit of FIG. 1B with the probe tips positioned at a maximal spacing.

[0028]FIG. 3A is a plan view of an embodiment of the single-end probeunit depicted in FIG. 1C.

[0029]FIG. 3B is a cross-sectional view of an embodiment of thesingle-end probe unit depicted in FIG. 1C.

[0030]FIG. 3C is an end view of an embodiment of the single-end probeunit depicted in FIG. 1C.

[0031]FIG. 3D is a side view of an embodiment of the single-end probeunit of FIG. 1C depicted with the probe tip and ground tip contactingsolder points on a printed circuit board.

[0032]FIG. 3E is an end view of an embodiment of the single-end probeunit of FIG. 1C with the ground tip positioned at a minimal spacing tothe probe tip.

[0033]FIG. 3F is an end view of an embodiment of the single-end probeunit of FIG. 1C with the ground tip positioned at a middle spacing tothe probe tip.

[0034]FIG. 3G is an end view of an embodiment of the single-end probeunit of FIG. 1C with the ground tip positioned at a maximal spacing fromthe probe tip.

[0035]FIG. 4 is a perspective view of an embodiment of the differentialprobe tip unit depicted in FIG. 1D.

[0036]FIG. 5 is a perspective view of an embodiment of the single-endprobe tip unit depicted in FIG. 1E.

[0037]FIG. 6 depicts exemplary probe tip units that may be implementedin various embodiments the differential and/or single-end probe tipunits of FIGS. 1D and 1E.

DETAILED DESCRIPTION

[0038] Having summarized the invention above, reference is now made indetail to the figures which depict exemplary embodiments of theinvention. Referring to FIG. 1A, a perspective view of an embodiment ofa probe amplifier unit 102 is shown. The probe amplifier unit 102includes an enclosure, housing, or other structure that encloses probeamplifier circuitry (not shown). Typically, such probe amplifiercircuitry supports a wideband active probing system that provides highbandwidth signal reception and low loading of connected probe tips. Forexample, the probe amplifier circuitry housed within the probe amplifierunit 102 may provide a probing bandwidth of at least 3 GHz.

[0039] The probe amplifier unit 102 may be constructed of variousmaterials. For example, the probe amplifier unit 102 may be constructedof various types of plastic material. Other materials may be used toconstruct the probe amplifier unit 102 within the scope of theinvention. Such other materials preferably should not interfere with theoperation or use of the probe amplifier unit 102.

[0040] A power supply/signal transmission cable 104 is typicallyconnected to the probe amplifier unit 102. The power supply/signaltransmission cable 104 typically includes cable insulation or sheathingthat covers various conductors. For example, the power supply/signaltransmission cable 104 may contain a coaxial conductor 105, such as acoaxial cable, for transmission of signals. Additionally, the powersupply/signal transmission cable 104 may contain one or more powerconductors 106, such as insulated copper conductors that are solid orstranded in configuration. Typically, the power conductors 106 containedwithin the power supply/signal transmission cable 104 are configured toprovide DC electrical power to the probe amplifier unit 102. Thus, forexample, the power conductors 106 may include a positive conductor, anegative conductor, and a ground conductor. However, the powerconductors 106 may also include additional conductors for the purpose ofproviding electrical power to the probe amplifier unit 102. The powersupply/signal transmission cable 104 may additionally include otherconductors for various purposes such as, for example, to transmitcontrol signals to/from the probe amplifier unit 102. It is noted thatin some embodiments (not depicted), the foregoing various conductors maynot be contained within a cable or within just a single cable. Further,the power supply/signal transmission cable 104 and/or the variousconductors contained therein may include other types of cables orconductors that serve the aforementioned purposes.

[0041] The power supply/signal transmission cable 104 is usuallyconnected to the probe amplifier unit 102 by a power supply/signaltransmission cable connector 108. The power supply/signal transmissioncable connector 108 may include one or more connectors and/orconnections to the probe amplifier unit 102 as depicted. For example,the coaxial conductor 105 of the power supply/signal transmission cable104 may be connected to the probe amplifier circuitry of the probeamplifier unit 102 by a coaxial connector 109. As another example, thepower conductors 106 of the power supply/signal transmission cable 104may be connected to the probe amplifier circuitry of the probe amplifierunit 102 by solder terminal connections (not shown). Various other typesof connectors and/or connections may be implemented to connect thevarious conductors of the power supply/signal transmission cable 104 tothe probe amplifier unit 102 within the scope of the invention.

[0042] The power supply/signal transmission cable connector 108 may alsoinclude a strain relief device 118. Such a strain relief device 118functions to prevent excessive strain from being placed on the variousconductors, connectors, and/or connections at the connection point ofthe power supply/signal transmission cable connector 108 to the probeamplifier unit 102. For example, if the probe amplifier unit 102 ishandled, strain may be transferred from the probe amplifier unit 102 tothe strain relief device 118 to the sheathing of the power supply/signaltransmission cable 104. In some embodiments, the power supply/signaltransmission cable connector 108 may also function as a strain reliefdevice. Various types and configurations of strain relief devices may beimplemented within the scope of the invention.

[0043] As indicated in FIG. 1A, the far end of the power supply/signaltransmission cable 104 is typically connected to monitoring and/ortesting equipment (not depicted). For example, the power supply/signaltransmission cable 104 may be connected to an oscilloscope or logicanalyzer. The far end of the power supply/signal transmission cable 104may also be connected to other types of equipment to facilitate thefunction of the probe amplifier unit 102.

[0044] One or more probe cables, examples of which are indicated byreference numerals 112 and 113, may also be connected to the probeamplifier unit 102. Typically, these probe cables 112, 113 conveysignals received by a probe unit (not shown) to the probe amplifier unit102. The probe cables 112, 113 may include cable insulation or sheathingthat contains one or more types of conductors. Typically, the probecables 112, 113 are insulated coaxial conductors (e.g., coaxial cables)that are adapted to convey signals to facilitate wideband probing. Theprobe cables 112, 113 may be substantially flexible to facilitatehandling of the probe amplifier unit 102 without causing substantialmovement of a connected probe unit. The probe cables 112, 113 mayinclude other types of conductors that serve to facilitate widebandprobing or other functions.

[0045] As depicted in FIG. 1A, the probe cables 112, 113 are typicallyconnected to the probe amplifier unit 102 by probe cable connectors 114,115, respectively. The probe cable connectors 114, 115 may include oneor more connectors and/or connections to the probe amplifier unit 102.For example, one or more of the probe cable connectors 114, 115 may becoaxial connectors. Typically, the probe cable connectors 114, 115provide a connection of the probe cables 112, 113 to the probe amplifiercircuitry contained within the probe amplifier unit 102. Various othertypes of connectors and/or connections may be implemented to connect theprobe cables 112, 113 to the probe amplifier unit 102 within the scopeof the invention.

[0046] The probe cable connectors 114, 115 may also include strainrelief devices, for example, as depicted. Such strain relief devicesprevent excessive strain from being placed on the various conductors,connectors, and/or connections at the connection points of the probecables 112, 113 to the probe amplifier unit 102. In some embodiments,the probe cable connectors 114, 115 may also function as strain reliefdevices, as depicted for example in FIG. 1A. Various other types andconfigurations of strain relief devices may also be implemented withinthe scope of the invention.

[0047] The probe cables 112, 113 are typical connected to a probe unit(not depicted). In this regard, FIGS. 1B-1E depict the probe amplifierunit 102 connected to various probe units by one or more probe cables112, 113.

[0048]FIG. 1B depicts the probe amplifier unit 102 connected to adifferential probe unit 200 by the probe cables 112, 113. FIG. 1Cdepicts the probe amplifier unit 102 connected to a single-end probeunit 300 by the probe cable 112. FIG. 1D depicts the probe amplifierunit 102 connected to a differential probe tip unit 400 by the probecables 112, 113. And, FIG. 1E depicts the probe amplifier unit 102connected to a single-end probe tip unit 500 by the probe cable 112. Theforegoing probe units will be discussed in further detail below.

[0049] As discussed above with respect to FIG. 1A, the probe amplifierunit 102 may facilitate wideband active probing by interfacing a probeunit to monitoring and/or testing equipment. In that regard, theimplementation of the probe amplifier unit 102 provides physical andelectrical features not provided by existing systems and methods. Thesefeatures overcome challenges posed by the increased complexity andcompactness of IC chip package configurations and the increasedperformance characteristics of IC devices. For example, theimplementation of the probe amplifier unit 102 provides high bandwidthsignal reception (e.g., 3 GHz or greater) and low loading of the probetips of a connected probe unit while allowing the probe amplifiercircuitry to be positioned remotely from the probe unit. Theimplementation of the probe amplifier unit 102 also provides otherbeneficial physical and electrical features that are not provided byexisting systems and methods. These additional features are discussedhereafter.

[0050] The implementation of the probe amplifier unit 102 to facilitatewideband active probing of IC devices provides the capability tosecurely connect a probe tip unit (e.g., the probe tip units 400, 500depicted in FIGS. 1D, 1E) to an IC device. This capability provides suchbenefits as hands-free probing and minimized parasitic input impedanceat the connection to the probe points. This capability to securelyconnect a probe tip unit is available for several reasons. One, theprobe tip unit does not need to include the probe amplifier circuitrysince that circuitry is remotely contained in the probe amplifier unit102. As a result, the probe tip unit is sufficiently small andlightweight to facilitate secure connections of the probe tip unit tothe probe points of an IC device (e.g., by soldering the probe tips ofthe probe tip unit to the probe points of an IC device on a PCB). Two,the probe tip unit is typically connected to the probe amplifier unit102 by one or more probe cables 112, 113. As discussed previously, theprobe cables 112, 113 are typically substantially flexible such that aprobe tip unit that is secured to an IC device is not physicallydisturbed by movement of the probe amplifier unit 102 or other connectedcomponents.

[0051] The implementation of the probe amplifier unit 102 to facilitatewideband active probing of IC devices also provides the capability toperform probing of an IC device while in operation. That is, a probe tipunit can be secured (e.g., by soldering) to the probe points of an ICdevice and the IC device can thereafter be probed while it is inoperation. For example, a PCB can be placed in its usual enclosure orcard-cage and probed while in operation. This is possible because of therelatively small size and light weight of the probe tip unit, since ittypically does not include the probe amplifier circuitry, and because ofthe flexibility of the probe cables 112, 113, which in thisimplementation do not include multiple types of conductors (e.g., signaland power) that tend to make a cable inflexible and bulky.

[0052] The implementation of the probe amplifier unit 102 for widebandactive probing also provides the capability to efficiently andinexpensively modify electrical characteristics of the wideband activeprobing system such as the damping resistance of the probe tips. This isbecause various probe units and probe tip units (e.g., the probe units200, 300 and probe tip units 400, 500 depicted in FIGS. 1B, 1C, 1D, and1E, respectively, and variations thereof) can be connected to the probeamplifier unit 102 to modify the electrical characteristics of theoverall probing system (i.e., the probe unit or probe tip unit, probeamplifier unit, and connecting conductors). This capability tointerchange probe tip units connected to the probe amplifier unit 102also provides the convenient and efficient capability to pre-secureprobe tip units to various IC devices and then connect the probeamplifier unit 102 to any one of the probe tip units while the IC deviceis in operation. This is convenient and efficient, for example, whenseveral IC devices are tested with one available active probing system.

[0053] Finally, the implementation of the probe amplifier unit 102 forwideband active probing provides an inexpensive capability to performwideband active probing on a variety of IC devices. Since the probeamplifier circuitry is contained in the probe amplifier unit 102 and notin the probe units, the probe units are less costly and, thus, variousprobe units can be obtained to conform to various physical andelectrical probing constraints at a lower overall expense than obtainingmultiple existing probe units that each include probe amplifiercircuitry. Additionally, probe tip units (e.g., the probe tip units 400,500) used with the probe amplifier unit 102 can be secured to probepoints without the concern of possibly damaging more costly existingprobe tip units that include probe amplifier circuitry.

[0054] It should be apparent from the foregoing discussion that theimplementation of the probe amplifier unit 102 for wideband activeprobing provides beneficial physical and electrical features notprovided by existing systems and methods. These features overcome thechallenges posed by the increased complexity and compactness of IC chippackage configurations and the increased performance characteristics ofIC devices. Having discussed several embodiments of the probe amplifierunit 102 as well as several benefits provided by the implementation ofthe probe amplifier unit 102 for wideband active probing, discussion isnow focused in more detail on several embodiments of probe units andprobe tip units that can be implemented, for example, with the probeamplifier unit 102 for wideband active probing.

[0055] FIGS. 2A-2G show various views of embodiments of a differentialprobe unit 200 of the present invention. As is known, a differentialprobe unit typically obtains two signals that are then manipulated (forexample by probe amplifier circuitry) to obtain a differential signal(i.e., the difference between the signals). The differential probe unit200 includes a probe unit housing 202 which typically contains variouscomponents of the differential probe unit 200. The probe unit housing202 may be constructed of various materials. For example, the probe unithousing 202 may be constructed of various types of plastic. Othermaterials may be used to construct the probe unit housing 202 that,preferably, do not interfere with the operation or use of thedifferential probe unit 200.

[0056] The differential probe unit 200 also includes probe barrels 204,205. The probe barrels 204, 205 are typically cylindrical in shape andhave an interior volume. Typically, the probe barrels 204, 205 areconstructed of an electrically conductive material, for example a metalor alloy, such that they function as electrical conductors. In someembodiments, various known probe barrel designs may be implemented forthe probe barrels 204, 205 within the scope of the invention.

[0057] As depicted for example in FIGS. 2A-2B, the probe barrels 204,205 typically extend partially outside of the probe unit housing 202such that a portion of the probe barrels 204, 205 are at least partiallysurrounded by and/or contained within the probe unit housing 202. Thelength of the portion of the probe barrels 204, 205 that extends outsideof the probe unit housing 202 may vary to facilitate various probingapplications. The probe barrels 204, 205 each typically extend out ofthe probe unit housing 202 through openings in the probe unit housing202 as depicted, for example, in FIG. 2C. Further, the probe barrels204, 205 may rest on portions of the internal structure (not shown) ofthe probe unit housing 202 in order to maintain the probe barrels 204,205 in a substantially consistent position when the differential probeunit 200 is handled or used for probing.

[0058] Probe barrel nose cones 206, 207 (also referred to as “probebarrel end caps”) extend from the ends of the probe barrels 204, 205that extend outside the probe unit housing 202. The probe barrel nosecones 206, 207 are typically substantially conical in shape, althoughother shapes may be implemented, and typically have an interior volume.Typically, the probe barrel nose cones 206, 207 are constructed of anelectrically non-conductive material, for example a plastic or rubber,such that they function as electrical insulators. In some embodiments,various known probe barrel nose cone designs may be implemented for theprobe barrel nose cones 206, 207 within the scope of the invention.

[0059] The longitudinal axes of the probe barrel nose cones 206, 207extend from the probe barrels 204, 205 at offset angles a1 and a2,respectively, from the longitudinal axes of the probe barrels 204, 205,as depicted for example in FIG. 2A. Typically, the offset angles a1, a2are each at least 15° and at most 25°. However, the offset angle a1, a2may be other independent values within the scope of the invention. Thebenefits of this offset angle feature of the probe barrel nose cones206, 207 will be discussed below.

[0060] Probe tips 208, 209 extend partially out of the ends of the probebarrel nose cones 206, 207, respectively, as depicted in FIGS. 2A-2B.Thus, a portion of each probe tip 208 and 209 is at least partiallysurrounded by a respective probe barrel nose cone 206 and 207. The probetips 208, 209 are typically constructed of a substantially conductivematerial, for example a metal or alloy, such that they function aselectrical conductors. The probe tips 208, 209 are typically cylindricalin shape, although other shapes may be implemented within the scope ofthe invention. Further, the probe tips 208, 209 may have ends withvarious shapes, for example pointed, in order to facilitate makingand/or maintaining physical electrical contact with probe points on adevice under test. The probe tips 208, 209 may include impedanceelements (not shown) to facilitate wideband active probing. In someembodiments, various known probe tip designs may be implemented for theprobe tips 208, 209.

[0061] The probe tips 208, 209 extend out of the probe barrel nose cones206, 207 substantially in line with the longitudinal axes of the probebarrel nose cones 206, 207, respectively. Thus, the longitudinal axes ofthe probe tips 208, 209 are offset from the longitudinal axes of theprobe barrels 204, 205, respectively, at substantially the offset anglesa1 and a2, which as discussed above, typically are each at least 15° andat most 25°. Further, as discussed above, the offset angles a1, a2 maybe other independent values. The benefits of this offset feature of theprobe tips 208, 209 will be discussed below.

[0062] Probe cables 212, 213 typically extend from within the interiorof the probe unit housing 202 to outside of the probe unit housing 202.As indicated for example in FIGS. 2A-2B, the far ends of the probecables 212, 213 typically connect to a probe amplifier (such as theprobe amplifier unit 102 depicted in FIG. 1A and discussed above).Further, as depicted for example in FIG. 2A, the local ends of the probecables 212, 213 connect to the probe barrels 204, 205, respectively. Theprobe cables 212, 213 may connect to the probe barrels 204, 205 invarious ways within the scope of the invention, including various knownways of connecting cables to probe barrels. The connection of the probecables 212, 213 to the probe barrels 204, 205 will be discussed furtherbelow.

[0063] The probe cables 212, 213 may include insulation or sheathingthat contains one or more types of conductors. Typically, the probecables 212, 213 are insulated coaxial conductors (e.g., coaxial cables)that are adapted to convey signals to facilitate wideband probing. Insome embodiments, the probe cables 212, 213 may be substantiallyflexible to facilitate handling of a connected probe amplifier unitwithout causing substantial movement of the differential probe unit 200.The probe cables 212, 213 may include other types of conductors thatserve to facilitate wideband active probing or other functions, withinthe scope of the invention.

[0064] One or more strain relief devices (not shown) may extend from theprobe unit housing 202 and attach to the probe cables 212, 213. Suchstrain relief devices serve to prevent excessive strain from beingplaced on the connections of the probe cables 212, 213 to the probebarrels 204, 205 and/or other components of the differential probe unit200. In some embodiments, various known types of strain relief devicesmay be implemented within the scope of the invention. Further, in someembodiments, one or more strain relief devices (not depicted) may beimplemented alternatively at the connection of the probe cables 212, 213to the probe barrels 204, 205.

[0065] The differential probe unit 200 may also include one or moreslots 214, 215, as depicted for example in FIGS. 2A and 2C. These slots214, 215 define openings to the interior of the probe unit housing 202such that the probe barrels 204, 205 are at least partially exposed. Theopenings defined by the slots 214, 215 may have various shapes, forexample a substantially rectangular shape as depicted in FIG. 2C.

[0066] One or more positioning elements 216, 217 may extend out of theslots 214, 215, respectively. The positioning elements 216, 217 areattached to the probe barrels 204, 205, respectively, such that movementof the positioning elements 216, 217 causes movement of the probebarrels 204, 205. The positioning elements 216, 217 may, for example, beimplemented as levers that are attached to the probe barrels 204, 205.But, other types of components that may serve to transfer movement tothe probe barrels 204, 205 through the slots 214, 215 may be implementedwithin the scope of the invention. Typically, the positioning elements216, 217 are constructed of a non-conductive material such as a plastic.Additionally, other methods may be implemented within the scope of theinvention to cause the movement of the probe barrels 204, 205. Forexample, internal gears, levers, and/or other such components inmechanical communication with external knobs, slide switches, and/orother such components (not depicted) may be implemented to cause themovement of the probe barrels 204, 205 within the scope of theinvention.

[0067] One or more elastic compressible elements 220, 221 may also beincluded in the differential probe unit 200. For example, as depicted inFIGS. 2A-2B, elastic compressible elements 220, 221 may engage betweenthe probe barrels 204, 205, respectively, and a portion of the probeunit housing 202. The elastic compressible elements 220, 221 may beimplemented, for example, as normally decompressed or lightly compressedhelical springs. In such an implementation, the elastic compressibleelements 220, 221 may at least partially surround a portion of the probecables 212, 213 within the probe unit housing 202, as depicted forexample in FIGS. 2A-2B.

[0068] The differential probe unit 200 may also include a groundconnector 224, as depicted for example in FIGS. 2A and 2C. The groundconnector 224 is typically constructed of a conductive material, such asa metal or alloy, such that it functions as an electrical conductor. Theground connector 224 is typically connected to or in substantial contactwith the probe barrels 204, 205 such that the probe barrels 204, 205 andthe ground connector 224 are in electrical communication and maintainsubstantially the same electrical potential. The ground connector 224may also be implemented at other locations of the differential probeunit and in other forms than that depicted in FIGS. 2A and 2C.

[0069] The combination of the probe cables 212, 213, the probe barrels204, 205, the probe barrel nose cones 206, 207, and the probe tips 208,209, respectively, typically serve to sense and convey signals, that areobtained for example from an IC device, to a probe amplifier andsubsequently to monitoring and/or testing equipment when thedifferential probe unit 200 is used to perform probing. In that regardtypically at least one conductor of the probe cables 212, 213 iselectrically connected to the probe barrels 204, 205, respectively, forexample a ground conductor. Further, typically at least one otherconductor of the probe cables 212, 213 is electrically connected to theprobe tips 208, 209, respectively, for example a signal conductor. Theseconnections may be made directly to the probe tips 208, 209 or throughvarious circuitry (not shown) internal to the probe barrels 204, 205and/or the probe barrel nose cones 206, 207. The probe tips 208, 209extend out of the probe barrel nose cones 206, 207, respectively, andare held in a substantially fixed position by at least the probe barrelnose cones 206, 207. Further, the probe barrel nose cones 206, 207typically electrically isolate the probe tips 208, 209 from the probebarrels 204, 205, respectively. Thus, when the probe tips 208, 209 arebrought into contact with probe points of an IC device, for example,signals are obtained by the probe tips 208, 209 that may be transmittedto a probe amplifier by one or more conductors of the probe cables 212,213 that are electrically connected to the probe tips 208, 209,respectively.

[0070] The combined structures of the probe barrels 204, 205, probebarrel nose cones 206, 207, and probe tips 208, 209, respectively, whichwill be collectively referred to hereafter as “probe assemblies”, may becapable of several position adjustments. The position adjustmentcapabilities of the probe assemblies are possible without temporarily orpermanently forcing the deformation of components of the probeassemblies. For example, the probe assemblies can be adjusted to variouspositions without bending or stretching components of the probeassemblies to conform to the positions of probe points. Further, theprobe assemblies are capable of position adjustments without degradingthe overall electrical features of the differential probe unit 200, suchas high bandwidth performance.

[0071] Each probe assembly is capable of retracting into the probe unithousing 202 along the longitudinal axis of the probe barrels 204, 205,respectively, as indicated in FIGS. 2A and 2D. The elastic compressibleelements 220, 221, which may engage the probe barrels 204, 205,typically maintain the probe assemblies partially extended out of theprobe unit housing 202. However, if pressure is applied to, for example,the probe tip 209, the respective probe assembly is able to retractpartially into the probe unit housing 202, as depicted for example inFIG. 2D. Further, when the pressure on the probe tip 208 is removed, theelastic compressible element 221 may cause the respective probe assemblyto re-extend out of the probe unit housing 202 to its typical partiallyextended position. The extent of retraction and extension of the probeassemblies may be limited, for example, by portions of the internalstructure of the probe unit housing 202. This capability of the probeassemblies to reciprocate (i.e., move in/out of the probe unit housing202) allows the probe tips 208, 209 to make effective contact with probepoints that are at different heights from a common surface, for exampletwo solder points on a PCB as depicted in FIG. 2D, when the differentialprobe unit 200 is utilized for probing. The probe cables 212, 213connected to the probe assemblies are arranged within the probe unithousing 202 to facilitate the reciprocating movement of the probeassemblies. For example, if the probe cables 212, 213 are attached to astrain relief device that extends from the probe unit housing 202 (asdescribed above), the strain relief device may allow sufficient movementof the probe cables 212, 213 in accordance with the reciprocatingmovement of the probe assemblies to avoid placing substantial strain onthe probe cables 212, 213. As another example, a sufficient portion ofthe probe cables 212, 213 may be stored within the probe unit housing202 to facilitate the reciprocating movement of the probe assemblieswithout placing substantial strain on the probe cables 212, 213.

[0072] Each probe assembly (i.e., probe barrel 204, 205, probe barrelnose cone 206, 207, and probe tip 208, 209, respectively) may also becapable of rotational movement about the longitudinal axis of the probebarrels 204, 205, respectively, as indicated for example in FIGS. 2E-2G.As described above, the internal structure of the probe unit housing 202is adapted to maintain the probe barrels 204, 205, and thus the probeassemblies, in a substantially consistent position when the differentialprobe unit 200 is handled or used for probing. In this regard, theinternal structure of the probe unit housing 202 is adapted to maintainthe probe assemblies in at least a substantially consistent rotationalposition with respect to the longitudinal axes of the probe barrels 204,205. Each probe assembly can be rotated about the longitudinal axis ofits respective probe barrel 204, 205 by, for example, applyingrotational force to the assembly. Once the probe assembly is rotated toa particular position, the internal structure of the probe unit housing202 causes it to maintain that rotational position during handling orprobing with the differential probe unit 200 due to, for example, thefrictional engagement of the probe barrels 204, 205 and the internalstructure of the probe unit housing 202. The probe cables 212, 213connected to the probe assemblies are arranged within the probe unithousing 202 to facilitate the rotational movement of the probeassemblies. For example, if the probe cables 212, 213 are attached to astrain relief device that extends from the probe unit housing 202 (asdescribed above), the strain relief device may allow sufficient movementof the probe cables 212, 213 in accordance with the rotational movementof the probe assemblies to avoid placing substantial strain on the probecables 212, 213. As another example, a sufficient portion of the probecables 212, 213 may be stored within the probe unit housing 202 tofacilitate the rotational movement of the probe assemblies withoutplacing substantial strain on the probe cables 212, 213.

[0073] As described above, the differential probe unit 200 may includeslots 214, 215 through which positioning elements 216, 217 extend, andpositioning elements 216, 217 may be attached to the probe barrels 204,205, respectively. In this regard, the positioning elements 216, 217 maybe an integral part of the probe assemblies. Thus, when force is appliedto one of the positioning elements 216, 217, it causes the respectiveprobe assembly to rotate accordingly. As depicted for example in FIGS.2E and 2G, the rotational movement of each probe assembly may be limitedwhen the positioning elements 216, 217 engage the sides of the slots214, 215, respectively. For example, with respect to FIG. 2E, if thepositioning element 217 is moved substantially upward, the respectiveprobe assembly will be rotated until the positioning element 217 engagesthe top edge of the slot 215. Thus, when the differential probe unit 200is used for probing, each probe assembly can be independently rotated toa desired position by moving the positioning elements 216, 217.Furthermore, the probe assemblies will remain in the desired position(as described above) when the positioning elements 216, 217 are nolonger moved.

[0074] The rotational capability of the probe assemblies and the offsetaxis configuration of the probe barrel nose cones 206, 207 and probetips 208, 209 from the probe barrels 204, 205 respectively, as describedabove, provides the benefit of a variable spacing capability between theprobe tips 208, 209. This variable spacing capability of the probe tips208, 209 facilitates probing of various configurations of probe points,for example of an IC device mounted on a PCB, without bending orstretching components of the probe assemblies or forcing the componentsto conform to probe point spacing by temporarily deforming them.Further, the variable spacing capability of the probe tips 208, 209 doesnot degrade the overall electrical features of the differential probeunit 200, such as high bandwidth performance.

[0075] FIGS. 2E-2G show exemplary depictions of the variable spacingcapability of the probe tips 208, 209. As depicted in FIG. 2E, when thepositioning elements 216, 217 are moved substantially upward until theyengage the top edge of the slots 214, 215, the probe assemblies may berotated such that the probe tips 208, 209 are positioned at a minimalspacing D1. This spacing D1 of the probe tips occurs because the probeassemblies are rotated such that the probe tips 208, 209 are tiltedinward due to their offset longitudinal axes from the longitudinal axesof the probe barrels 204, 205, respectively, as discussed above.Similarly, FIG. 2F depicts the positioning levers 216, 217 moved to aposition approximately midway between the top and bottom edges of theslots 214, 215, and accordingly, the probe assemblies may be rotatedsuch that the probe tips 208, 209 are positioned at a spacing D2 whichis greater than spacing D1. Finally, in FIG. 2G, the positioningelements are moved substantially downward to engage the bottom edge ofthe slots 214, 215 causing the probe assemblies to rotate such that theprobe tips 208, 209 may be positioned at a maximal spacing D3 which isgreater than spacing D2. At this position, the probe tips 208, 209 aretilted outward due to their offset longitudinal axes from thelongitudinal axes of the probe barrels 204, 205, respectively, asdiscussed above.

[0076] It is noted for clarity that the foregoing descriptions withrespect to FIGS. 2E-2G are exemplary of the variable spacingcapabilities of the probe tips 208, 209, but are not exclusive. Forexample, depending on the embodiment of the differential probe unit 200,the positioning and spacing of the probe tips 208, 209 with respect tothe positions of the positioning elements 216, 217 may vary from what isdepicted in FIGS. 2E-2G and described in the foregoing.

[0077] Discussion is now focused on another group of probe unitembodiments of the present invention. FIGS. 3A-3G depict various viewsof embodiments of a single-end probe unit 300 of the present invention.As is known, a single-end probe unit, in contrast to a differentialprobe unit, typically obtains a signal with respect to ground, such as avoltage signal from an IC device. The single-end probe unit 300 includesa probe unit housing 302 which typically contains various components.The probe unit housing 302 is typically substantially cylindrical andhas an interior volume. Further, the probe unit housing 302 is typicallyconstructed of an electrically non-conductive material, for example aplastic or rubber, such that it functions as an electrical insulator. Insome embodiments, various known probe housing designs may be implementedfor the probe unit housing 302 within the scope of the invention.

[0078] The single-end probe unit 300 further includes a probe barrel304. The probe barrel 304 is typically cylindrical in shape and has aninterior volume. Typically, the probe barrel 304 is constructed of anelectrically conductive material, for example a metal or alloy, suchthat it functions as an electrical conductor. In some embodiments,various known probe barrel designs may be implemented for the probebarrel 304.

[0079] As depicted in FIGS. 3A-3B, the probe barrel 304 typicallyextends partially outside of the probe unit housing 302 such that aportion of the probe barrel 304 is at least partially surrounded byand/or contained within the probe unit housing 302. The length of theportion of the probe barrel 304 that extends outside of the probe unithousing 302 may vary to facilitate various probing applications. Theprobe barrel 304 typically extends out of the probe unit housing 302through an opening in the probe unit housing 302 as depicted in FIG. 3C.Further, the probe barrel 304 may rest on portions of the internalstructure (not shown) of the probe unit housing 302 in order to maintainthe probe barrel 304 in a substantially consistent position when thesingle-end probe unit 300 is handled or used for probing.

[0080] A probe barrel nose cone 306 (also referred to as a “probe barrelend cap”) extends from the end of the probe barrel 304 that extendsoutside the probe unit housing 302. The probe barrel nose cone 306 istypically substantially conical in shape, although other shapes may beimplemented, and typically has an interior volume. Typically, the probebarrel nose cone 306 is constructed of an electrically non-conductivematerial, for example a plastic or rubber, such that it functions as anelectrical insulator. In some embodiments, various known probe barrelnose cone designs may be implemented for the probe barrel nose cone 306.

[0081] The longitudinal axis of the probe barrel nose cone 306 extendsfrom the probe barrel 304 at an offset angle a3 from the longitudinalaxis of the probe barrel 304, as depicted for example in FIG. 3A.Typically, the offset angle a3 is at least 15° and at most 25°. However,the offset angle a3 may be other values within the scope of theinvention. The benefits of this offset feature will be discussed below.

[0082] A probe tip 308 extends partially out of the end of the probebarrel nose cone 306 as depicted in FIGS. 3A-3B. Thus, a portion of theprobe tip 308 is at least partially surrounded by the probe barrel nosecone 306. The probe tip 308 is typically cylindrically shaped, althoughother shapes may be implemented within the scope of the invention. Theprobe tip 308 is typically constructed of a substantially conductivematerial, for example a metal or alloy, such that it functions as anelectrical conductor. The probe tip 308 may include one or moreresistive elements (not shown) to facilitate wideband active probing.Further, the end of the probe tip 308 may have various shapes, forexample pointed, to facilitate making and/or maintaining contact with aprobe point. In some embodiments, various known probe tip designs may beimplemented for the probe tip 308.

[0083] The probe tip 308 extends out of the probe barrel nose cone 306substantially in line with the longitudinal axes of the probe barrelnose cone 306. Thus, the longitudinal axis of the probe tip 308 isoffset from the longitudinal axis of the probe barrel 304 atsubstantially the offset angle a3, which as discussed above, typicallyis at least 15° and at most 25°. Further, as discussed above, the offsetangle a3 may be other values. The benefits of this offset feature of theprobe tip 308 will be discussed below.

[0084] The single-end probe unit 300 also includes a ground tip unit 314that is attached to the probe barrel 304. The ground tip unit 314 has aground tip connector 315 which is typically substantially annularshaped. The ground tip connector 315 at least partially surrounds aportion of the probe barrel 304 that extends from the probe unit housing302. The ground tip connector 315 is adapted to maintain the ground tipunit 314 in a substantially consistent position when the single-endprobe unit 300 is handled or used for probing.

[0085] A ground tip receptacle 316 is connected to the ground tipconnector 315. The ground tip receptacle 316 is typically cylindrical inshape and has an interior volume. A ground tip 317 extends from insideof the ground tip receptacle 316. The ground tip 317 is typicallycylindrical in shape, although other shapes may be implemented. The endof the ground tip 317 may have various shapes, for example pointed, tofacilitate making and/or maintaining contact with a probe point. Theground tip 317 extends partially outside of the interior of the groundtip receptacle 316 such that a portion of the ground tip 317 is at leastpartially surrounded by and/or contained within the ground tipreceptacle 316. The end of the ground tip 317 that is partiallysurrounded by and/or contained within the ground tip receptacle 316 andthe internal structure of the ground tip receptacle 316 are typicallyadapted such that the ground tip 317 is retained at least partiallywithin the ground tip receptacle 316. For example, as depicted in FIG.2B, the end of the ground tip 317 may be flared to a diameter that iswider than the opening in the ground tip receptacle 316 through whichthe ground tip 317 extends such that the flared end engages the internalstructure of the ground tip receptacle 316.

[0086] As depicted in FIG. 3B, the ground tip unit 314 may also includean elastic compressible element 320 disposed within the ground tipreceptacle 316. The elastic compressible element 320 typically engagesthe end of the ground tip 317 and a portion of the internal structure ofthe ground tip receptacle 316. The elastic compressible element 320 maybe implemented, for example, as a normally decompressed or lightlycompressed helical spring.

[0087] The components of the ground tip unit 314, i.e. the ground tipconnector 315, the ground tip receptacle 316, the ground tip 317, andthe elastic compressible element 320, are typically constructed of asubstantially conductive material, for example a metal or alloy, suchthat they function as electrical conductors. Further, these componentsof the ground tip unit 314 are typically in electrical communication.

[0088] The longitudinal axes of the ground tip receptacle 316 and theground tip 317 are typically substantially in-line. Further, the groundtip unit 314 is typically attached to the probe barrel 304 such that thelongitudinal axes of the ground tip receptacle 316 and the ground tip317 are typically substantially parallel to the longitudinal axis of theprobe barrel 304.

[0089] A probe cable 312 typically extends from within the interior ofthe probe unit housing 302 to outside of the probe unit housing 302. Asindicated for example in FIGS. 3A-3B, the far end of the probe cable 312typically connects to a probe amplifier (such as the probe amplifierunit 102 depicted in FIG. 1A and discussed above). Further, as depictedfor example in FIG. 3A, the local end of the probe cable 312 connects tothe probe barrel 304. The probe cable 312 may connect to the probebarrel 304 in various ways within the scope of the invention, includingvarious known ways of connecting a cable to a probe barrel. Theconnection of the probe cable 312 to the probe barrel 304 will bediscussed further below.

[0090] The probe cable 312 may include insulation or sheathing thatcontains one or more types of conductors. Typically, the probe cable 312is an insulated coaxial conductor (e.g., a coaxial cable) that isadapted to convey signals to facilitate wideband probing. In someembodiments, the probe cable 312 may be substantially flexible tofacilitate handling of a connected probe amplifier unit without causingsubstantial movement of the single-end probe unit 300. The probe cable312 may include other types of conductors that serve to facilitatewideband active probing or other functions, within the scope of theinvention.

[0091] A strain relief device 318 may extend from the probe unit housing302 and attach to the probe cable 312, as depicted for example in FIGS.3A-3B. The strain relief device 318 serves to prevent excessive strainfrom being placed on the connection of the probe cable 312 to the probebarrel 304 and/or other components of the single-end probe unit 300. Insome embodiments, various known types of strain relief devices may beimplemented. Further, in some embodiments, a strain relief device (notdepicted) may be implemented alternatively at the connection of theprobe cable 312 to the probe barrel 304.

[0092] The combination of the probe cable 312, the probe barrel 304, theprobe barrel nose cone 306, the probe tip 308, and the ground tip unit314 typically serve to convey signals, that are obtained for examplefrom an IC device, to a probe amplifier and subsequently to monitoringand/or testing equipment when the single-end probe unit 300 is utilizedto perform probing. In that regard, typically at least one conductor ofthe probe cable 312 is electrically connected to the probe barrel 304,for example a ground conductor. The ground tip unit 314 is typicallyconnected in electrical communication with the probe barrel 304 by theground tip connector 315 such that the ground tip 317 is in electricalcommunication with the probe barrel 304.

[0093] Typically, at least one other conductor of the probe cable 312 iselectrically connected to the probe tip 308, for example a signalconductor. This connection may be made directly to the probe tip 308 orthrough various circuitry (not shown) internal to the probe barrel 304and/or the probe barrel nose cone 306. The probe tip 308 extends out ofthe probe barrel nose cone 306 and is held in a substantially fixedposition by at least the probe barrel nose cone 306. Further, the probebarrel nose cone 306 typically electrically isolates the probe tip 308from the probe barrel 304. Thus, when the probe tip 308 and ground tip317 are brought into contact with probe points of an IC device, forexample, signals are obtained by the probe tip 308 which may betransmitted to a probe amplifier by one or more conductors of the probecable 312 that are electrically connected to the probe tip 308.

[0094] The ground tip unit 314 may be capable of several positionadjustments. The position adjustment capabilities of the ground tip unit314, which are described hereafter, are possible without temporarily orpermanently forcing the deformation of components of the ground tip unit314. For example, the ground tip unit 314 can be adjusted to variouspositions without bending or stretching the components of the ground tipunit 314 to, for example, conform to the positions of probe points.Further, the ground tip unit 314 is capable of position adjustmentswithout degrading the overall electrical features of the single-endprobe unit 300, such as high bandwidth performance.

[0095] The ground tip 317 may be capable of retracting into the groundtip receptacle 316, as indicated for example in FIGS. 3A, 3B and 3D. Theelastic compressible element 320, which may engage the ground tip 317,typically maintains the ground tip 317 partially extended out of theground tip receptacle 316. However, if pressure is applied to the groundtip 317, for example by contact with a probe point, the ground tip 317is able to retract partially into the ground tip receptacle 316, asdepicted for example in FIG. 3D. Further, when the pressure on theground tip 317 is removed, the elastic compressible element 320, whichtypically engages the ground tip 317 and a portion of the internalstructure of the ground tip receptacle 316, causes the ground tip 317 tore-extend out of the ground tip receptacle 316 to its typical partiallyextended position. The extent of retraction and extension of the groundtip 317 may be limited by, for example, portions of the internalstructure of the ground tip receptacle 316, as discussed above. Thecapability of the ground tip 317 to reciprocate (i.e., move in/out ofthe ground tip receptacle 316) allows the probe tip 308 and ground tip317 to make effective contact with probe points (e.g., a signal probepoint and a ground probe point) that are at different heights from acommon surface. For example, the probe tip 308 and ground tip 317 areable to make effective contact with two solder points at differentheights on a PCB, as depicted for example in FIG. 3D, when thesingle-end probe unit 300 is utilized for probing. The probe tip 317 andthe probe tip receptacle 316 are adapted such that the ground tip 317maintains electrical communication with the probe barrel 304 during thereciprocating movement of the probe tip 317 in and out of the probe tipreceptacle 316. The elastic compressible element 320 may also serve tomaintain the ground tip 317 in electrical communication with the probebarrel 304 in cooperation with the probe tip 317 and the probe tipreceptacle 316.

[0096] The ground unit 314 may also be capable of rotational movementabout the longitudinal axis of the probe barrel 304, as indicated forexample in FIGS. 3E-3G. As described above, the ground tip connector 315is adapted to maintain the ground tip unit 314 in a substantiallyconsistent position when the single-end probe unit 300 is handled orused for probing. In this regard, the ground tip connector 315 isadapted to maintain the ground tip unit 314 in a substantiallyconsistent rotational position with respect to the longitudinal axis ofthe probe barrel 304. The ground tip unit 314 can be rotated about thelongitudinal axis of the probe barrel 304 by, for example, applying arotational force to it. Once the ground tip unit 314 is rotated to aparticular position, the ground tip connector 315 causes the ground tipunit 314 to maintain that rotational position during handling or probingwith the single-end probe unit 300 due to, for example, the frictionalengagement of the ground tip connector 315 and the probe barrel 304. Theground tip connector 315 is adapted such that the ground tip 317maintains electrical communication with the probe barrel 304 during therotational movement of the probe tip unit 314 about the longitudinalaxis of the probe barrel 304.

[0097] The rotational capability of the ground tip unit 314 and theoffset axis configuration of the probe barrel nose cone 306 and probetip 308 from the probe barrel 304, as described above, provides thebenefit of a variable spacing capability between the probe tip 308 andthe ground tip 317. This variable spacing capability between the probetip 308 and the ground tip 317 facilitates probing of variousconfigurations of probe points, for example of an IC device mounted on aPCB, without bending or stretching components of the single-end probeunit 300 or forcing the components to conform to probe point spacing bytemporarily deforming them. Further, the variable spacing capabilitybetween the probe tip 308 and the ground tip 317 does not degrade theoverall electrical features of the single-end probe unit 300, such ashigh bandwidth performance.

[0098] FIGS. 3E-3G show exemplary depictions of the variable spacingcapability between the probe tip 308 and the ground tip 317. As depictedin FIG. 3E, when the ground tip unit 314 is rotated to a first positionabout the longitudinal axis of the probe barrel 304, the probe tip 308and the ground tip 317 are positioned at a minimal spacing S1. Thisspacing S1 between the probe tip 308 and the ground tip 317 occursbecause the ground tip unit 314 is rotated such that the probe tip 308is tilted toward the ground tip 317 due to the offset longitudinal axisof the probe tip 308 from the longitudinal axis of the probe barrel 304,as discussed above. Similarly, FIG. 3F depicts the ground tip unit 314rotated to a second position about the longitudinal axis of the probebarrel 304 such that the probe tip 308 and the ground tip 317 arepositioned at a spacing S2, which is greater than spacing S1. Finally,in FIG. 3G, the ground tip unit 314 is rotated to a third position aboutthe longitudinal axis of the probe barrel 304 such that the probe tip308 and the ground tip 317 are positioned at a maximal spacing S3, whichis greater than spacing S2. At this position, the ground tip unit 314 isrotated such that the probe tip 308 is tilted away from the ground tip317 due to the offset longitudinal axis of the probe tip 308 from thelongitudinal axis of the probe barrel 304, as discussed above.

[0099] Having discussed several embodiments of probe units above,discussion is now focused on several embodiments of probe tip units ofthe present invention. In that regard, FIG. 4 depicts a differentialprobe tip unit 400 of the present invention. As is known, a differentialprobe tip unit typically obtains two signals, from an IC device forexample, that are then manipulated (for example by probe amplifiercircuitry) to obtain a differential signal (i.e., the difference betweenthe signals).

[0100] The differential probe tip unit 400 includes a probe unit housing402 which may contain various probe tip unit circuitry (not shown)ranging from conductor traces to various resistive, capacitive, and/orother electronic elements. The probe unit housing 402 may be constructedof various materials, such as various types of plastic. Other materialsmay be used to construct the probe unit housing 402, preferably that donot interfere with the operation or use of the differential probe tipunit 400, within the scope of the invention.

[0101] The differential probe tip unit 400 includes probe tip units 406,407 which are connected to the probe tip unit circuitry at the probeconnection points 404, 405, respectively. The probe tip units 406, 407include probe tips 408, 409, respectively. The probe tip units 406, 407may also include probe impedance elements 410, 411, respectively, tofacilitate wideband active probing using the differential probe tip unit400. The probe connection points 404, 405 may be implemented by varioustypes of electrical connections, for example solder connections orcompression terminal connections, which are all within the scope of theinvention.

[0102] The components of the probe tip units 406, 407 are typicallysubstantially electrically conductive such that the probe tips 408, 409are in electrical communication with the probe connection points 404,405, respectively. For example, the probe tips 408, 409 are typicallyconstructed of electrically conductive material, such as a metal oralloy. The probe tips 408, 409 may have various shapes, for examplecylindrical, to facilitate their connections to probe points of, forexample, an IC device.

[0103] Probe cables 412, 413 typically extend from within the interiorof the probe unit housing 402 to outside of the probe unit housing 402.As indicated for example in FIG. 4, the far ends of the probe cables412, 413 typically connect to a probe amplifier (such as the probeamplifier unit 102 depicted in FIG. 1A and discussed above). The localends of the probe cables 412, 413 typically connect to the probe tipunit circuitry (not shown) within the probe unit housing 402. The probecables 412, 413 may connect to the probe tip unit circuitry in variousways within the scope of the invention, for example by solderconnections or compression terminal connections.

[0104] The probe cables 412, 413 may include cable insulation orsheathing that contains one or more types of conductors. Typically, theprobe cables 412, 413 are insulated coaxial conductors (i.e., coaxialcables) that are adapted to convey signals to facilitate widebandprobing. The probe cables 412, 413 are typically substantially flexibleto facilitate handling of a connected probe amplifier unit withoutcausing substantial movement of the differential probe tip unit 400. Theprobe cables 412, 413 may include other types of conductors that serveto facilitate wideband active probing or other functions, within thescope of the invention.

[0105] One or more strain relief devices 418 may extend from the probeunit housing 402 and attach to the probe cables 412, 413. Such strainrelief devices 418 serve to prevent excessive strain from being placedon the connections of the probe cables 412, 413 to the probe tip unitcircuitry and/or other components of the differential probe tip unit400. In some embodiments, various known types of strain relief devicesmay be implemented within the scope of the present invention.

[0106] The combination of the probe cables 412, 413 and the probe tipunits 406, 407, respectively, typically serve to convey signals, thatare obtained for example from an IC device, to a probe amplifier andsubsequently to monitoring and/or testing equipment when thedifferential probe tip unit 400 is utilized to perform probing. In thatregard, typically at least one conductor of the probe cables 412, 413 iselectrically connected to the probe tip units 406, 407, respectively,for example a signal conductor. These connections may be made directlyto the probe tip units 406, 407 or through various probe tip unitcircuitry (not shown) internal to the probe unit housing 402. Further,atypically t least one other conductor of the probe cables 412, 413 iselectrically connected to the ground circuitry of the probe tip unitcircuitry (not shown), for example a ground conductor. In this regard,when the probe tips 408, 409 are brought into contact with probe pointsof an IC device, signals are obtained by the probe tip units 406, 407which may be transmitted to a probe amplifier by one or more conductorsof the probe cables 412, 413 that are electrically connected to theprobe tip units 406, 407, respectively.

[0107] The differential probe tip unit 400 is typically adapted tofacilitate hands-free and in-operation probing. In that regard, thedifferential probe tip unit 400 is typically adapted to be small-sizedand lightweight such that the probe tip units 406, 407 can be securelyconnected to probe points of, for example, an IC device that is mountedon a PCB. The flexibility of the probe cables 412, 413, as discussedabove, also facilitates such hands-free probing by minimizing physicaldisturbance of the differential probe tip unit 400 when connectedequipment, such as a probe amplifier, are handled or repositioned.Typically, the probe tip units 406, 407 are secured by soldering theprobe tips 408, 409 to the probe points, although other types ofconnections may be implemented within the scope of the invention.Preferably, connections are made in a manner, such as by soldering, tominimize the parasitic input impedance to the probe tip units 406, 407at the connections to the probe points.

[0108] The small size and light weight of the differential probe tipunit 400, as well as the flexibility of the probe cables 412, 413, alsofacilitates in-operation probing. Thus, the probe tip units 406, 407 canbe secured to probe points on a PCB which is placed in normal operationby inserting it into an enclosure or card-cage. This capabilityfacilitates more effective monitoring and/or testing to, for example,troubleshoot a problem component or PCB circuitry. Further, thiscapability facilitates connecting several differential probe units 400to various probe points so that efficient in-operation probing can beconducted using a single probe amplifier that is connected to each ofthe differential probe units 400 as needed.

[0109] Electrical characteristics of a wideband active probing system,such as the damping resistance of the probe tips, can be efficiently andinexpensively modified by utilizing various embodiments of thedifferential probe tip unit 400 that have different electricalcharacteristics. The electrical characteristics of the differentialprobe tip unit 400 may be varied by, for example, modifying the internalprobe tip unit circuitry and/or the probe tips. In that regard, variousconfigurations of probe tip units 406, 407 may be implemented with thedifferential probe tip unit 400.

[0110]FIG. 6 shows several configurations of probe tip units, amongothers, that may be implemented with the differential probe tip unit400. Solder-on probe tip units 601 and plug-on probe tip units 602 aretwo exemplary configurations of probe tip units shown. There are alsoSMT (surface-mount technology) grabber probe tip units 603 and wedgeprobe tip units 604. Many other configurations of probe tip units can beimplemented with the differential probe tip unit 400 within the scope ofthe invention.

[0111] Since the probe tip units 406, 407 are connected to thedifferential probe tip unit 400 at the connection points 404, 405, theprobe tip units 406, 407 can be replaced efficiently and inexpensivelyif, for example, there is a need to modify the electricalcharacteristics of the probing system or an existing probe tip unit isdamaged. In that regard, the probe tip units 406, 407 can be replacedwith other probe tip units, such those depicted in FIG. 6 by, forexample, de-soldering the existing probe tip units 406, 407 from theconnection points 404, 405 and soldering replacement probe tip units tothe connection points 404, 405. Alternatively, several differentialprobe tip units 400 can be configured with various probe tip units 406,407 to be implemented as needed for probing.

[0112]FIG. 5 depicts a single-end probe tip unit 500 of the presentinvention. As is known, a single-end probe tip unit, in contrast to adifferential probe tip unit, typically obtains a signal with respect toground, such as a voltage from an IC device. The single-end probe tipunit 500 includes a probe unit housing 502 which may contain variousprobe tip unit circuitry (not shown) ranging from conductor traces tovarious resistive, capacitive, and/or other electronic elements. Theprobe unit housing 502 may be constructed of various materials, such asvarious types of plastic. Other materials may be used to construct theprobe unit housing 502, preferably that do not interfere with theoperation or use of the single-end probe tip unit 500, within the scopeof the invention.

[0113] The single-end probe tip unit 500 includes probe tip units 506,507 which are connected to the probe tip unit circuitry at the probeconnection points 504, 505, respectively. The probe tip units 506, 507include probe tips 508, 509, respectively. The probe tip units 506, 507may also include probe impedance elements 510, 511, respectively, tofacilitate wideband active probing using the single-end probe tip unit500. The probe connection points 504, 505 may be implemented by varioustypes of electrical connections, for example solder connections orcompression terminal connections, and are all within the scope of theinvention.

[0114] The components of the probe tip units 506, 507 are typicallysubstantially electrically conductive such that the probe tips 508, 509are in electrical communication with the probe connection points 504,505, respectively. For example, the probe tips 508, 509 are typicallyconstructed of electrically conductive material, such as a metal oralloy. The probe tips 508, 509 may have various shapes, for examplecylindrical, to facilitate connections to probe points of, for example,an IC device.

[0115] A probe cable 512 typically extends from within the interior ofthe probe unit housing 502 to outside of the probe unit housing 502. Asindicated for example in FIG. 5, the far end of the probe cable 512typically connects to a probe amplifier (such as the probe amplifierunit 102 depicted in FIG. 1A and discussed above). The local end of theprobe cable 512 typically connects to the probe tip unit circuitry (notshown) within the probe unit housing 502. The probe cable 512 mayconnect to the probe tip unit circuitry in various ways within the scopeof the invention, for example by solder connections or compressionterminal connections.

[0116] The probe cable 512 may include cable insulation or sheathingthat contains one or more types of conductors. Typically, the probecable 512 is an insulated coaxial conductor (e.g., a coaxial cable) thatis adapted to convey signals to facilitate wideband probing. The probecable 512 is typically substantially flexible to facilitate handling ofa connected probe amplifier unit without causing substantial movement ofthe single-end probe tip unit 500. The probe cable 512 may include othertypes of conductors that serve to facilitate wideband active probing orother functions, within the scope of the invention.

[0117] A strain relief devices 518 may extend from the probe unithousing 502 and attach to the probe cable 512. Such a strain reliefdevice 518 serves to prevent excessive strain from being placed on theconnections of the probe cable 512 to the probe tip unit circuitryand/or other components of the single-end probe tip unit 500. In someembodiments, various known types of strain relief devices may beimplemented within the scope of the present invention.

[0118] The combination of the probe cable 512 and the probe tip units506, 507 typically serve to convey signals, that are obtained forexample from an IC device, to a probe amplifier and subsequently tomonitoring and/or testing equipment when the single-end probe tip unit500 is utilized to perform probing. In that regard, typically at leastone conductor of the probe cable 512 is electrically connected to theprobe tip unit 506, for example a signal conductor. Further, typicallyat least one other conductor of the probe cable 512 is electricallyconnected to the probe tip unit 507, for example a ground conductor.These connections may be made directly to the probe tip units 506, 507or through various probe tip unit circuitry (not shown) internal to theprobe unit housing 502. In this regard, when the probe tips 508, 509 arebrought into contact with probe points of an IC device, for example,signals are obtained by the probe tip units 506, 507 which may betransmitted to a probe amplifier by one or more conductors of the probecable 512 that are electrically connected to the probe tip units 506,507, respectively.

[0119] The single-end probe tip unit 500 is typically adapted tofacilitate hands-free and in-operation probing. In that regard, thesingle-end probe tip unit 500 is typically adapted to be small-sized andlightweight such that the probe tip units 506, 507 can be securelyconnected to probe points of, for example, an IC device that is mountedon a PCB. The flexibility of the probe cable 512, as discussed above,also facilitates such hands-free probing by minimizing physicaldisturbance of the single-end probe tip unit 500 when connectedequipment, such as a probe amplifier, are handled or repositioned.Typically, the probe tip units 506, 507 are secured by soldering theprobe tips 508, 509 to the probe points, although other types ofconnections may be implemented within the scope of the invention.Preferably, connections are made in a manner, such as by soldering, tominimize the parasitic input impedance to the probe tip units 506, 507at the connections to the probe points.

[0120] The small size and light weight of the single-end probe tip unit500, as well as the flexibility of the probe cable 512, also facilitatesin-operation probing. Thus, the probe tip units 506, 507 can be securedto probe points on a PCB which is placed in normal operation byinserting it into an enclosure or card-cage. This capability facilitatesmore effective monitoring and/or testing to, for example, troubleshoot aproblem component or PCB circuitry. Further, this capability facilitatesconnecting several single-end probe units 500 to various probe points sothat efficient in-operation probing can be conducted using a singleprobe amplifier that is connected to each of the single-end probe units500 as needed.

[0121] Electrical characteristics of a wideband active probing system,such as the damping resistance of the probe tips, can be efficiently andinexpensively modified by utilizing various embodiments of thesingle-end probe tip unit 500 that have different electricalcharacteristics. The electrical characteristics of the single-end probetip unit 500 may be varied, for example, by modifying the internal probetip unit circuitry and/or the probe tips. In that regard, variousconfigurations of probe tip units 506, 507 may be implemented with thesingle-end probe tip unit 500. For example, FIG. 6 shows severalconfigurations of probe tip units, among others, that may beimplemented. There are solder-on probe tip units 601 and plug-on probetip units 602. There are also SMT (surface-mount technology) grabberprobe tip units 603 and wedge probe tip units 604. Many otherconfigurations of probe tip units can be implemented on the single-endprobe tip unit 500 within the scope of the invention.

[0122] Since the probe tip units 506, 507 are connected to thesingle-end probe tip unit 500 at the connection points 504, 505, theprobe tip units 506, 507 can be replaced efficiently and inexpensivelyif, for example, there is a need to modify the electricalcharacteristics of the probing system or an existing probe tip unit isdamaged. In that regard, the probe tip units 506, 507 can be replacedwith other probe tip units, such those depicted in FIG. 6, by, forexample, de-soldering the existing probe tip units 506, 507 from theconnection points 504, 505 and soldering replacement probe tip units tothe connection points 504, 505. Alternatively, several single-end probeunits 500 can be configured with various probe tip units 506, 507 to beimplemented as needed for probing.

[0123] It should be understood that throughout the foregoing discussionof the present invention, references made to the probing of IC devicesare merely exemplary, and the probing of other electrical circuitsand/or electronic devices applies to such references within the scope ofthe invention.

[0124] It should be further understood that the above-describedembodiments of the present invention are merely possible examples ofimplementations, merely set forth for a clear understanding of theprinciples of the invention. Many variations and modifications may bemade to the above-described embodiments of the invention withoutdeparting substantially from the spirit and principles of the invention.All such modifications and variations are intended to be included hereinwithin the scope of this disclosure and the present invention andprotected by the following claims.

Therefore, having thus described the invention, at least the followingis claimed:
 1. An apparatus for amplification of probe signals in awideband active probing system, comprising: a probe amplifier housing; aprobe amplifier circuitry at least partially contained within saidhousing, wherein said probe amplifier circuitry and said probe amplifierhousing are configured to be separately arranged and positioned fromconnected probing and signal monitoring apparatuses.
 2. The apparatus ofclaim 1, further comprising: a first connection port electricallyconnected to said probe amplifier circuitry and configured toelectrically connect at least one power supply conductor and at leastone signal transmission conductor to said probe amplifier circuitry; anda second connection port electrically connected to said probe amplifiercircuitry and configured to electrically connect at least one signaltransmission conductor to said probe amplifier circuitry.
 3. Theapparatus of claim 1, further comprising: at least one power supplyconductor and at least one signal transmission conductor electricallyconnected to said probe amplifier circuitry.
 4. A system for widebandactive probing of devices and circuits in operation, comprising: a probeamplifier unit that comprises probe amplifier circuitry; a firstplurality of conductors electrically connected to said probe amplifiercircuitry that comprises at least one power supply conductor and atleast one signal transmission conductor; a signal monitoring apparatusconfigured to monitor electrical signals and in electrical communicationwith said probe amplifier circuitry through said first plurality ofconductors; a second plurality of conductors electrically connected tosaid probe amplifier circuitry that comprises at least one signaltransmission conductor; and a probing apparatus configured to probeelectrical circuits and in electrical communication with said probeamplifier circuitry through said second plurality of conductors.
 5. Thesystem of claim 4, wherein said probing apparatus is a single-end probeor a differential probe.
 6. The system of claim 4, wherein said probingapparatus comprises a probe housing and at least one probe tip inelectrical communication with said second plurality of conductors. 7.The system of claim 6, wherein said probe tip is configured to beattached to a probe point.
 8. The system of claim 6, wherein said probetip is detachable from said probing apparatus and said probing apparatusis configured for the attachment of a substitute probe tip in place ofsaid probe tip.
 9. The system of claim 4, wherein said signal monitoringapparatus is an oscilloscope or a logic analyzer.
 10. The system ofclaim 4, wherein: said first plurality of conductors comprises a powersupply cable having at least two power supply conductors, and a coaxialcable having at least two signal transmission conductors; and saidsecond plurality of conductors comprises a coaxial cable having at leasttwo signal transmission conductors.
 11. The system of claim 4, whereinsaid second plurality of conductors is configured to be more flexiblethan said first plurality of conductors.
 12. The system of claim 4,wherein: said first plurality of conductors is attached to said probeamplifier unit by at least a first strain relief; and said secondplurality of conductors is attached to said probe amplifier unit by atleast a second strain relief.
 13. A method for wideband active probingof devices and circuits in operation, comprising the steps of: providinga probe amplifier unit that comprises probe amplifier circuitry;electrically connecting a first plurality of conductors to said probeamplifier circuitry; electrically connecting a signal monitoringapparatus to said first plurality of conductors to place said signalmonitoring apparatus in electrical communication with said probeamplifier circuitry; electrically connecting a second plurality ofconductors to said probe amplifier circuitry; electrically connecting aprobing apparatus to said second plurality of conductors to place saidprobing apparatus in electrical communication with said probe amplifiercircuitry; probing an electrical circuit with said probing apparatus;and monitoring signals with said signal monitoring apparatus that areobtained during said step of probing.
 14. The method of claim 13,wherein said step of probing comprises attaching said probing apparatusto at least one probe point of an electrical circuit so that electricalsignals are obtained from the probe point by said probing apparatus. 15.The method of claim 13, wherein said probing apparatus comprises a probehousing and at least one probe tip configured to attach to a probepoint, wherein said probe tip is detachable from said probing apparatusand said probing apparatus is configured for the attachment of asubstitute probe tip in place of said probe tip, and further comprisingthe steps of: detaching said probe tip from said probing apparatus; andattaching a substitute probe tip to said probing apparatus.
 16. A systemfor wideband active probing of devices and circuits in operation,comprising: means for amplifying a probe signal; means for power supplyand signal transmission electrically connected to said means foramplifying; means for monitoring signals electrically connected to saidmeans for power supply and signal transmission and in electricalcommunication with said means for amplifying via said means for powersupply and signal transmission; means for signal transmissionelectrically connected to said means for amplifying; and means forprobing an electrical circuit electrically connected to said means forsignal transmission and in electrical communication with said means foramplifying via said means for signal transmission.